BUFFALO, NEW YORK—A new survey of southeastern Alaska conducted by geologist Alia Lesnek of the University at Buffalo suggests a boat route headed southward into the New World would have been mostly free of ice some 17,000 years ago, according to a report in Science Magazine. To determine how long rocks from four islands along the southeastern coast of Alaska had been exposed to air, Lesnek measured the concentration of beryllium-10 in the rocks. Since cosmic rays change individual oxygen-16 atoms in quartz to beryllium-10 atoms, higher levels of beryllium-10 translate to longer exposure. The study also indicates that the early migrants from Beringia would have found plenty of plant and animal life along the Pacific coastline. Lesnek and her colleagues reexamined animal bones recovered from caves, and adjusted their radiocarbon dates for the effects of marine diets. The results suggest that the oldest bones had been left behind by carnivores some 45,000 years ago. The researchers also found a lack of bones dating to between 20,000 and 17,000 years ago, which could suggest the area had been covered in ice in the years before the Beringians took to the sea. To read in-depth about excavations in southwestern Alaska, go to “Cultural Revival.”
